Image forming apparatus

ABSTRACT

A friction member that abuts against a rotating member being fixed to a display portion and that stops the rotating member being fixed to a display portion by frictional resistance of an abutting surface accommodates the rotating member into a predetermined accommodating position in a reliable manner by changing a frictional force of the friction member.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No. 15/494,143, filed Apr. 21, 2017, which claims priority to Japanese Patent Application No. 2016-087538, filed Apr. 25, 2016, each of which is hereby incorporated by reference herein in their entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The present disclosure relates to image forming apparatuses, such as a copier and a printer.

Description of the Related Art

Hitherto, a proposal has been made for image forming apparatuses such as, for example, a copier and a laser printer, that adopt an electrophotographic method. In the proposal, an operation unit is tilted (inclined) so that a person with low height and a person on a wheelchair can operate the image forming apparatus.

An operation unit of an image forming apparatus proposed in Japanese Patent Laid-Open No. 2010-102143 provides a free stop hinge at a rotation center of the tilting operation unit. Hitherto, the free stop hinge is, typically, provided with a torque limiter, a torsion spring, or the like.

In conventional operation units that provide a torque limiter or the like at the rotation center, reactive force acts in a direction opposite to the tilting direction, and a phenomenon occurs in which the operation unit is moved back in the direction of the reactive force when the tilting is stopped. Such a phenomenon causes a problem in which when the operation unit is tilted, for example, to stop the operation unit at a certain angle, the operation unit becomes lifted and cannot be set at that certain angle. Because of the above, the user needs to attempt tilting the operation unit once more disadvantageously causing the user to feel irritated.

Accordingly, the present disclosure provides an image forming apparatus that is capable of adjusting an inclination angle of a rotating member by using frictional force, and that prevents the rotating member from being lifted from an accommodating position when the rotating member is accommodated in the accommodating position.

SUMMARY OF THE INVENTION

The present disclosure provides an image forming apparatus including an image forming unit that forms an image, the image forming apparatus including a display portion that displays a state of the image forming unit, an accommodating portion in which the display portion is accommodated, a rotating member being fixed to the display portion and being rotatably supported by a support portion provided in the accommodating portion such that the display portion is configured to pivot in a vertical direction, wherein the display portion is capable of being pivoted with respect to the accommodating portion such that a center of mass of the display portion that has been pivoted from the accommodating portion is vertically above a center of mass of the display portion accommodated in the accommodating portion, and an applying member provided in the accommodating portion so as to come into surface contact with the rotating member, the applying member applying frictional force to the rotating member, the applying member being provided in the accommodating portion such that an area in contact with the rotating member is, in a case in which a predetermined position where the center of mass of the display portion that has been pivoted from the accommodating portion in the vertical direction is above the center of mass of the display portion accommodated in the accommodating portion is positioned further above, larger than an area in contact with the rotating member in a case in which the center of mass of the display portion that has been pivoted from the accommodating portion is positioned at or below the predetermined position. In the image forming apparatus, the display portion in which the center of mass is positioned vertically above the predetermined position is stopped by the frictional force applied by the applying member, and the display portion in which the center of mass is positioned at or below the predetermined position is pivoted by a weight of the display portion and is accommodated in the accommodating portion.

Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an entirety of an image forming apparatus according to a first exemplary embodiment of the present disclosure.

FIG. 2 is a diagram for describing an operation unit and a liquid crystal display portion of the first exemplary embodiment of the present disclosure.

FIGS. 3A and 3B are diagrams for describing a shaft (FIG. 3A) and a hole (FIG. 3B) in a recess portion of the operation unit according to the first exemplary embodiment of the present disclosure.

FIGS. 4A and 4B are diagrams for describing a hole (FIG. 4A) and a tilt arm (FIG. 4B) of the liquid crystal display portion according to the first exemplary embodiment of the present disclosure.

FIGS. 5A and 5B are diagrams for describing a configuration (FIG. 5A) and a cross-section of a pivoting portion (FIG. 5B) of the liquid crystal display portion according to the first exemplary embodiment of the present disclosure.

FIG. 6 is a diagram for describing a moment created by an own weight of the liquid crystal display portion according to the first exemplary embodiment of the present disclosure.

FIG. 7 is a diagram for describing a relationship between a pivot angle of the liquid crystal display portion and a moment created by an own weight of the liquid crystal display portion according to the first exemplary embodiment of the present disclosure.

FIGS. 8A and 8B are diagrams for describing an area of an abutting portion (FIG. 8A), and a relationship between the pivot angle of the liquid crystal display portion and the area of the abutting portion (FIG. 8B) according to the first exemplary embodiment of the present disclosure.

FIGS. 9A and 9B are diagrams for describing a sheet and an abutting portion of a tilt arm (FIG. 9A), and reactive force of the sheet (FIG. 9B) according to the first exemplary embodiment of the present disclosure.

FIG. 10 is a diagram for describing a relationship between the pivot angle of the liquid crystal display portion, and the moment created by the own weight of the liquid crystal display portion and a torque needed to pivot the tilt arm, according to the first exemplary embodiment of the present disclosure.

FIGS. 11A and 11B are diagrams in which FIG. 11A is a diagram in which an arm holding plate has been removed, and FIG. 11B illustrates an abutting portion, according to a second exemplary embodiment of the present disclosure.

FIGS. 12A and 12B are diagrams for describing the arm holding plate (FIG. 12A), and the abutting portion between a tilt arm and the arm holding plate (FIG. 12B), according to the second exemplary embodiment of the present disclosure.

FIGS. 13A and 13B are diagrams for describing a positional relationship between the tilt arm and the arm holding plate in a case in which a pivot angle of a liquid crystal display portion according to the second exemplary embodiment of the present disclosure is 45° (FIG. 13A), and a deformation amount of a sheet (FIG. 13B).

FIGS. 14A and 14B are diagrams for describing a positional relationship between the tilt arm and the arm holding plate in a case in which the pivot angle of the liquid crystal display portion according to the second exemplary embodiment of the present disclosure is 0° (FIG. 14A), and a deformation amount of a sheet (FIG. 14B).

FIG. 15 is a diagram for describing the pivot angle and the deformation amount of the sheet of the liquid crystal display portion according to the second exemplary embodiment of the present disclosure.

FIG. 16 is a diagram for describing a relationship between the pivot angle of the liquid crystal display portion, and a moment created by an own weight of the liquid crystal display portion and a torque needed to pivot a tilt arm, according to the second exemplary embodiment of the present disclosure.

DESCRIPTION OF THE EMBODIMENTS First Exemplary Embodiment

The present disclosure can be used in a unit that pivots (a pivoting unit) included in an apparatus main body of an image forming apparatus; however, herein, an example of a case in which the present disclosure is used in a tilting liquid crystal display portion will be given. Hereinafter, an operation unit of a printer serving as an image forming apparatus will be described. Note that the present disclosure is not limited to a printer and may be applied to an image forming apparatus, such as a multifunction apparatus.

FIG. 1 is an outside drawing of a printer 100. The printer 100 includes a feed unit 101 at the bottom, an image forming unit 102 at the middle, and a sheet discharge unit 103 at the top. Since the printer 100 operates in a typical manner, description of the operation will be omitted. An operation unit 200 is disposed on an upper surface of the printer 100. A liquid crystal display portion 201 that displays an operation state (information) of the printer 100 is disposed in the operation unit 200.

Furthermore, various types of keys, such as a keypad 202, for inputting the number of prints are disposed in the operation unit 200. The liquid crystal display portion 201 includes a tilt mechanism that enables the liquid crystal display portion 201 to be viewed easily when it is difficult to view due to a reflection of a lighting unit or when a person with low height or a person on a wheelchair need to view the liquid crystal display portion 201 easily.

Tilt Mechanism

A configuration of the tilting liquid crystal display portion 201 serving as a rotating member will be described next. FIG. 2 is a diagram illustrating a recess portion 200 c serving as an accommodating portion that accommodates the liquid crystal display portion 201. The liquid crystal display portion 201 is housed inside the recess portion 200 c of the operation unit 200. The liquid crystal display portion 201 pivots about a shaft 200 a provided on a lateral side of the recess portion 200 c and a hole 200 b provided in a coaxial manner with respect to the shaft 200 a, which are illustrated in FIGS. 3A and 3B. In the rotation center, a hole 201 a provided on a lateral side of the liquid crystal display portion 201 illustrated in FIG. 4A engages with the shaft 200 a. On the other side of the liquid crystal display portion 201, a shaft 203 b of a tilt arm 203 that pivots in an integral manner with the liquid crystal display portion 201 engages with the hole 200 b of the operation unit 200. In other words, the liquid crystal display portion 201 is rotatably supported by the operation unit 200. Furthermore, pivoting of the liquid crystal display portion 201 is restricted by a pivot stopper (not shown) such that the liquid crystal display portion 201 can be pivoted at a pivot angle (a tilt angle) ranging from 0° to 90°. FIGS. 5A and 5B are diagrams illustrating a configuration of the tilt mechanism. The shaft 203 b of the tilt arm 203 is supported by the hole 200 b, and a shaft 203 c at an end portion of the tilt arm 203 is supported by an arm holding plate 204. The tilt arm 203 includes a fan-shaped arm 203 a between the shaft 203 b and the shaft 203 c. The arm holding plate 204 is fixed, together with a sheet holding plate 205, to a lateral side on the outside of the operation unit recess portion 200 c with screws 206. An elastically deforming sheet 207 that has a highly frictional surface 207 a and that serves as a friction applying member is attached to the sheet holding plate 205. The highly frictional surface 207 a of the sheet 207 abuts against a lateral side of the fan-shaped arm 203 a of the tilt arm 203, and is elastically deformed in a direction of the pivot axis. The liquid crystal display portion 201 stops due to frictional resistance between the sheet 207 and the portion of the tilt arm 203 abutting against the sheet 207. In other words, the liquid crystal display portion 201 is configured so that the liquid crystal display portion 201 can be self-supported by the frictional resistance between the sheet 207 and the portion of the tilt arm 203 abutting against the sheet 207.

Feature of Present Disclosure

A feature of the present disclosure is that the tilting liquid crystal display portion can be prevented from being accommodated at a misaligned position with respect to a predetermined accommodating position due to reactive force when accommodating the tilting liquid crystal display portion to the predetermined accommodating position. Details thereof will be described.

Referring first to FIG. 6, a moment pivoting the liquid crystal display portion 201 created by the weight of the liquid crystal display portion 201 itself will be described. The moment (N·mm) pivoting the liquid crystal display portion by its own weight is expressed by the following equation, where m (kg) is the weight of the liquid crystal display portion 201, Lt (mm) is the distance between a rotation center 201 b and a center of mass 201 c of the liquid crystal display portion 201, and θ (°) is the pivot angle of the liquid crystal display portion 201.

Mt=9.8×m×Lt×cos θ

Note that θ is an angle formed between the liquid crystal display portion and a horizontal plane.

When the axis of abscissas is the pivot angle of the liquid crystal display portion 201, and the axis of ordinates is the moment, a relationship illustrated in FIG. 7 is established such that when θ=0°, Mt is the largest, and when θ=90°, Mt is the smallest.

In order to stop the liquid crystal display portion 201, a torque generating unit that generates a torque in the pivot shaft that is higher in load than Mt needs to be provided. However, as is the case of the tilting touch panel, in a case in which pressing force is applied to the liquid crystal display portion, taking such moment into account, a torque generating unit generating an accordingly larger torque is needed.

In the present exemplary embodiment, a liquid crystal display portion that is not a touch panel type and that includes a torque generating unit that uses frictional resistance will be described. As described above, the lateral side of the fan-shaped arm 203 a of the tilt arm 203 receives reactive force from the sheet 207 upon elastic deformation of the sheet 207. As illustrated in FIGS. 8A and 8B, it is assumed that P (N/mm²) is the pressure of the sheet 207, S (mm²) is an area of a contact surface 208 (the hatched portion) between the sheet 207 and the arm 203 a, μ is the friction coefficient of the surface of the sheet 207, and Ls (mm) is the distance from the rotation center 201 b of the liquid crystal display portion 201 to a center of the contact surface between the sheet 207 and the arm 203 a. When the moment pivoting the liquid crystal display portion 201 by its own weight is excluded, the torque Ts (N·mm) needed to pivot the tilt arm 203 is as follows.

Ts=μ×P×S×Ls

In a case in which a value obtained by subtracting the moment Mt pivoting the liquid crystal display portion 201 by its own weight from Ts described above is positive, then the liquid crystal display portion 201 is self-supported, and in a case in which the value is negative, then the liquid crystal display portion is not self-supported and is pivoted by its own weight. The present exemplary embodiment is configured so that when the pivot angle θ of the liquid crystal display portion 201 is around 0°, the pivot angle of the liquid crystal display portion reliably moves to 0°. Hatched portions in FIG. 9A illustrate the areas S of the contact surfaces 208 between the tilt arm 203 and the sheet 207 when the pivot angles θ are 0°, 45°, and 90°. FIG. 9B is a graph illustrating the relationship between the pivot angle θ and the area S of the contact surface 208. As featured in the graph, the contact areas S around pivot angle θ=0° are small compared with the contact areas S other than around pivot angle θ=0°.

FIG. 10 is a diagram illustrating the relationship between Mt and Ts. Since the contact area S changes against the pivot angle θ in the above manner, Ts also changes, as illustrated in the diagram. Since the value Ts−Mt is positive when the pivot angle θ is in range B, the liquid crystal display portion 201 is self-supported. Since the value Ts−Mt is negative when the pivot angle θ is in range A, the liquid crystal display portion 201 is not self-supported. Accordingly, in the range around pivot angle θ=0°, the liquid crystal display portion 201 is pivoted by its own weight and stops at 0°. As described above, when the pivot angle θ is in range A, the liquid crystal display portion 201 can be reliably accommodated at 0°. The present exemplary embodiment is configured so that, in a case in which the pivot angle is equivalent to or smaller than a predetermined angle (10° or smaller), the liquid crystal display portion 201 is not self-supported and is accommodated in the recess portion 200 c. Furthermore, in the present exemplary embodiment, the torque needed to pivot the liquid crystal display portion 201 in a case in which the pivot angle θ is a first angle θ1 that is smaller than the predetermined angle is smaller than the torque needed to pivot the liquid crystal display portion 201 in a case in which the pivot angle θ is a second angle θ2 that is larger than the predetermined angle.

Furthermore, regarding the effect of the present disclosure, since the frictional force gradually changes when the pivot angle is in range A, when the liquid crystal display portion 201 is pushed downwards, the liquid crystal display portion 201 is slowly pivoted by its own weight in range A and can be accommodated at 0° in a very smooth manner. In other words, the liquid crystal display portion 201 is configured so that the frictional force of the sheet 207 is applied when the pivot angle of the liquid crystal display portion 201 with respect to the recess portion 200 c is in at least range A as well. Accordingly, even in the range where the liquid crystal display portion 201 cannot be self-supported, the liquid crystal display portion 201 can be slowly accommodated into the accommodating portion.

Note that in the present exemplary embodiment, although a unit including a liquid crystal display portion is described as the pivoting unit, the same applies to a case in which an operation unit that includes keys and the like is tilted. Furthermore, although the present exemplary embodiment is configured so that a torque Ts (frictional force) needed for pivoting is generated in the entire range (0° to 90°) where pivoting can be performed, not limited to the above, for example, there may be a range where there is no generation of frictional force. However, it is desirable that Ts be positive in the entire range.

Furthermore, the present exemplary embodiment is configured so that the value Ts−Mt is positive in range B; however, not limited to the above, for example, the value does not have to be positive where the pivot angle is around 90°. However, it is desirable that the value Ts−Mt be positive in range B. Furthermore, in a case in which the value Ts−Mt is positive in range B, there may be a range where Ts becomes smaller as the pivot angle becomes larger.

Note that the sheet 207 may be provided on the tilt arm 203, and a contact surface (a plate) that comes into contact with the sheet 207 provided on the tilt arm 203 may be provided in the operation unit 200. In a case in which such a configuration is employed, an opening or a recess portion that is in non-contact with the sheet 207 may be provided in the movement path of the sheet 207 and in the operation unit 200 such that the contact area between the sheet 207 and the contact surface provided in the operation unit 200 in a case in which the pivot angle is larger than the predetermined angle (larger than 10°) is larger than the contact area between the sheet 207 and the contact surface provided in the operation unit 200 in which the pivot angle is equivalent to or smaller than the predetermined angle (10° or smaller).

Second Exemplary Embodiment

A second exemplary embodiment is different from the first exemplary embodiment in that while the contact area S between the tilt arm 203 and the sheet 207 is uniform, the amount of elastic deformation of the sheet 207 changes with the pivot angle θ of the liquid crystal display portion 201. A configuration of the torque generating unit is the same as that of the first exemplary embodiment. FIGS. 11A and 11B is a diagram illustrating a state in which the arm holding plate 204 has been removed. The sheet 207 is elastically deformed in the hatched area with the fan-shaped arm 203 a of the tilt arm 203. A mechanism for changing the amount of elastic deformation (an inroad amount) of the sheet 207 will be described next. The present exemplary embodiment is configured such that the amount of elastic deformation of the sheet 207 in the thickness direction is capable of being changed in accordance with the pivot angle θ of the liquid crystal display portion 201. FIG. 12A depicts a torque generating unit. As illustrated in FIG. 12B, the arm holding plate 204 includes a protrusion 204 a on the surface that opposes the fan-shaped arm 203 a of the tilt arm 203. Meanwhile, the fan-shaped arm 203 a of the tilt arm 203 includes a recess portion 203 d on the surface opposing the arm holding plate 204. A center line CL1 of the protrusion 204 a and a center line CL2 of the recess portion 203 d are lines that both pass through the rotation center of the liquid crystal display portion 201, and the angle formed by the lines is set so as to coincide with the pivot angle θ of the liquid crystal display portion 201. Upon pivoting of the liquid crystal display portion 201, the hatched portion of the fan-shaped arm 203 a of the tilt arm 203 and the protrusion 204 a of the arm holding plate 204 abut against each other. As an example, states in which the pivot angle θ of the liquid crystal display portion 201 is 45° and 0° will be described. FIG. 13A illustrates phases of the protrusion 204 a of the arm holding plate 204 and the recess portion 203 d of the fan-shaped arm 203 a when the pivot angle θ of the liquid crystal display portion 201 is 45°. The angle formed between the center line CL1 of the protrusion 204 a and the center line CL2 of the recess portion 203 d is the same as the pivot angle of the liquid crystal display portion 201, that is, θ=45°. FIG. 13B depicts the deformation amount of the sheet 207 in the above state. The protrusion 204 a of the arm holding plate 204 abuts against the surface of the fan-shaped arm 203 a positioned higher than the recess portion 203 d of the fan-shaped arm 203 a, and the sheet 207 is elastically deformed D45 (m). FIG. 14A illustrates phases of the protrusion 204 a of the arm holding plate 204 and the recess portion 203 d of the fan-shaped arm 203 a when the pivot angle θ of the liquid crystal display portion 201 is 0°. The center line CL1 of the protrusion 204 a and the center line CL2 of the recess portion 203 d coincide each other. FIG. 14B depicts the deformation amount of the sheet 207 in the above state, and the sheet 207 is elastically deformed D0 (m). In cases in which the pivot angles θ of the liquid crystal display portion 201 are 45° and 0°, the deformation amount of the sheet 207 is smaller at 0°, and the difference (D45−D0) between the deformation amounts of the sheet 207 coincides with the recessed amount of the recess portion 203 d of the fan-shaped arm 203 a. FIG. 15 illustrates a graph between the pivot angle θ of the liquid crystal display portion 201 and the amount of elastic deformation D of the sheet.

As described above, when the moment pivoting the liquid crystal display portion 201 by its own weight is excluded, the torque Ts (N·mm) needed to pivot the tilt arm 203 is as follows.

Ts=μ×P×S×Ls

The sheet 207 uses a member that generates a pressure P (N/mm²) that is proportional to the elastically deformed amount. In the present exemplary embodiment, the contact area S between the tilt arm 203 and the sheet 207 is uniform throughout all of the pivot angles θ of the liquid crystal display portion 201; accordingly, Ts changes in a manner similar to the change in the amount of elastic deformation D against the pivot angle θ. FIG. 16 illustrates a relationship between Mt and Ts, and similar to the first exemplary embodiment, when the pivot angle θ is in range A, the liquid crystal display portion 201 can be reliably accommodated at 0°. Note that in the present exemplary embodiment, while the contact area S is uniform throughout all of the pivot angles θ of the liquid crystal display portion 201, as in the first exemplary embodiment, even when the contact area S changes in the present exemplary embodiment, a similar effect can be obtained.

Furthermore, a similar effect can be obtained with a configuration in which the friction coefficient μ of the surface of the sheet 207 changes with the change in the pivot angle θ of the liquid crystal display portion 201.

The present disclosure is, in an image forming apparatus capable of adjusting an inclination angle of a rotating member by using frictional force, capable of preventing the rotating member from being lifted from an accommodating position with reactive force generated in the rotating member when accommodating the rotating member in the accommodating position.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. 

What is claimed is:
 1. An image forming apparatus including an image forming unit that forms an image, the image forming apparatus comprising: a display portion that displays a state of the image forming unit; an accommodating portion in which the display portion is accommodated; a rotating member being fixed to the display portion and being rotatably supported by a support portion provided in the accommodating portion such that the display portion is configured to pivot in a vertical direction, wherein the display portion is capable of being pivoted with respect to the accommodating portion such that a center of mass of the display portion that has been pivoted from the accommodating portion is vertically above a center of mass of the display portion accommodated in the accommodating portion; and an applying member provided in the accommodating portion so as to come into surface contact with the rotating member, the applying member applying frictional force to the rotating member, the applying member being provided in the accommodating portion such that an area in contact with the rotating member is, in a case in which a predetermined position where the center of mass of the display portion that has been pivoted from the accommodating portion in the vertical direction is above the center of mass of the display portion accommodated in the accommodating portion is positioned further above, larger than an area in contact with the rotating member in a case in which the center of mass of the display portion that has been pivoted from the accommodating portion is positioned at or below the predetermined position, wherein the display portion in which the center of mass is positioned vertically above the predetermined position is stopped by the frictional force applied by the applying member, and the display portion in which the center of mass is positioned at or below the predetermined position is pivoted by a weight of the display portion and is accommodated in the accommodating portion. 